Pediatric Genitourinary and Renal System Study Notes

Pediatric Genitourinary and Renal System Overview

• Efficiency and Function: Pediatric kidneys are significantly less efficient than adult kidneys at concentrating urine, clearing medications, and filtering waste products.
• Growth and Development: Kidneys continue to grow through adolescence.
• Bladder Capacity: The bladder capacity of a newborn infant at birth is approximately $1\,\text{ounce}$.
• Injury Susceptibility: Pediatric kidneys are more susceptible to physical injury compared to adults.
• Common Alterations: Major pediatric GU alterations include enuresis, cryptorchidism, hypospadias, epispadias, testicular torsion, inguinal hernias, and hydroceles.

Toilet Training and Developmental Readiness

• Developmental Task: Toilet training is one of the primary developmental tasks of toddlerhood. It aligns with Erikson’s goals of developing independence and autonomy.
• Average Age of Readiness: Most children are developmentally ready to begin toilet training between $2$ and $2.5\,\text{years}$ of age.
• Readiness Categories:
  • Physical Readiness: The child must feel the urge to void or defecate.
  • Mental Readiness: The child must possess the willingness or desire to use the toilet.
  • Psychologic Readiness: The child exhibits a desire for independence.
  • Parental Readiness: Caregivers must be prepared to commit time and patience to the process.
• Atraumatic Training Strategies:
  • Allow the child to progress at their own speed.
  • Ensure all caregivers agree on the training methods used.
  • Take the child's unique temperament and characteristics into account.
  • Avoid scolding, punishing, or overreacting to accidents.
  • Plan ahead for travel.
  • Use praise for successes and avoid power battles over the toilet.

Milestones in Bladder Control Development

• $1.5\,\text{years}$: The child passes urine at regular intervals.
• $2\,\text{years}$: The child announces when they are currently voiding.
• $2.5\,\text{years}$: The child makes the need to void known and is capable of holding urine.
• $3\,\text{years}$: The child can go to the bathroom independently; they may hold the urge if they are preoccupied with play.
• $2.5\text{ to }3.5\,\text{years}$: The child achieves nighttime bladder control.
• $4\,\text{years}$: The child shows interest in using bathrooms when away from home (e.g., movies, shopping centers).
• $5\,\text{years}$: The child voids approximately $7\,\text{times}$ a day, prefers privacy, and can initiate bladder emptying regardless of how full the bladder is.

Enuresis

• Definition: Involuntary voiding of urine beyond the expected age for voluntary bladder control. It is classified as a symptom rather than a disease.
• Diagnostic Threshold: Diagnosis is typically not made until the child is at least $5-6\,\text{years}$ of age.
• Demographics: More common in boys, particularly the nocturnal type. There is a strong familial tendency.
• Classification:
  • Nocturnal: Bedwetting that occurs only at night.
  • Diurnal: Wetting that occurs during the day.
  • Primary: The child has never achieved a consistent period of being dry at night (often related to small bladder capacity).
  • Secondary: Wetting occurs after the child has already been successfully toilet trained; often associated with stress, infections, or regression (e.g., hospital-induced stress).
• Causes:
  • Organic (Physical): UTI, diabetes insipidus, constipation, small bladder capacity, or neurologic/developmental disorders.
  • Non-Organic (Functional): Deep sleep patterns, sleep apnea, harsh training methods, regression, or life changes/stress.
• Treatment (TRAIN):
  • Train/Teach: Assess family coping and understanding.
  • Restrict Fluids: Limit intake prior to bedtime.
  • Active Practice: Perform pelvic muscle exercises.
  • Initiate Bladder Training: Encourage the child to drink fluids and hold urine as long as possible to increase functional bladder capacity.
  • Conditioning Therapy: Use of a "Potty Pager" or bed-wetting alarm.
• Pharmacotherapy:
  • Desmopressin (DDAVP): An oral medication that concentrates urine. Nursing indications include restricting fluids $1\,\text{hour}$ before administration and continuing restriction for $8\,\text{hours}$ after. It is given at bedtime for children over $6\,\text{years}$ old.
  • Oxybutynin chloride (Ditropan): Used for children with small bladder capacity.
  • Tricyclic Antidepressants (Imipramine): Used only as a last resort when other modalities fail.

Dosage Calculation Example

• Patient Weight: $17\,\text{lbs } 12\,\text{ounces}$.
  • Conversion: $17.75\,\text{lb} \div 2.2 = 8.06\,\text{kg}$.
• Order: Oxybutynin $1.6\,\text{mg}$ PO TID.
• Recommended Dose: $0.2\,\text{mg/kg/dose}$ two to three times daily.
• Calculation: $0.2\,\text{mg/kg} \times 8.06\,\text{kg} \approx 1.6\,\text{mg/dose}$.
• Safety Check: The ordered dose of $1.6\,\text{mg}$ PO TID is safe.

Structural Congenital Abnormalities

• Cryptorchidism (Undescended Testes):
  • Absence of one or both testes from the scrotum. Testes usually descend from the abdomen through the inguinal canal in utero.
  • If unilateral, usually right-sided.
  • Most descend by $3\,\text{months}$ of age. If not descended by $1\,\text{year}$, the child must be referred to a urologist due to risks of sterility and malignancy.
• Hypospadias and Epispadias:
  • Epispadias: The urethral meatus is located on the dorsal (top) side of the penis.
  • Hypospadias: The urethral meatus is located on the ventral (underside) of the penis.
  • Management: Surgical repair usually occurs between $6\,\text{months}$ and $1\,\text{year}$. Crucial: The infant should not be circumcised, as the foreskin may be needed for surgical repair.
  • Postoperative Care: Assess urinary drainage and pain. Use compression dressings to decrease edema. Administer antibiotics and antispasmodics (oxybutynin) for bladder spasms. Tub baths are prohibited until the dressing is removed.

Testicular Torsion

• Definition: An acute surgical emergency where blood flow to the testis is interrupted due to twisting.
• Time Sensitivity: There is a critical $6\,\text{hour}$ window for detorsion to salvage the ischemic testicle.
  • Salvage Rate ($<6\,\text{hours}$): $\sim 90\%$.
  • Salvage Rate ($6-12\,\text{hours}$): $\sim 50\%$.
  • Salvage Rate ($>12\,\text{hours}$): $< 10\%$.
• Symptoms: Sudden onset of unilateral pain, nausea, vomiting, and anorexia. The affected testicle typically "rides high" in the scrotum.
• Cremasteric Reflex: Evaluated by stroking the inner thigh. A normal reflex results in the testicle rising. In torsion, this reflex is often absent. An absent reflex carries a high suspicion for torsion.
• Demographics: Most common during puberty; the neonatal period is the second most common.
• Diagnosis: Color Doppler Ultrasound shows a lack of vascularity/blood flow.

Inguinal Hernia and Hydrocele

• Inguinal Hernia:
  • Caused by a patent processus vaginalis.
  • A groin/scrotal bulge that increases with crying or straining; contains abdominal contents (bowel).
  • Red Flags: Never force a painful hernia back into place. Notify the provider immediately for emergency surgery assessment.
  • Transillumination: Does not transilluminate.
• Hydrocele:
  • Fluid collection within the scrotum; usually painless and soft.
  • Transillumination: Positive (glows red/pink).
  • Management: Most congenital hydroceles resolve by $12\,\text{months}$. Surgical repair is considered if it persists after $1-2\,\text{years}$ or is associated with a hernia.
• Postoperative Care for Hernia Repair: Keep incision clean and dry, change diapers promptly and leave them loose, avoid strenuous activity for $2-3\,\text{weeks}$, and provide sponge baths only until cleared.

Urinary Tract Infection (UTI)

• Pathogen: The most common cause is E. coli.
• Neonatal Demographics: Boys are affected $5\times$ more often than girls during the first $3\,\text{months}$ (often linked to structural issues). Uncircumcised boys have a higher incidence.
• Post-Infancy Demographics: More common in girls, peaking around age $4$; incidence increases in adolescence with sexual activity.
• Cystitis (Lower UTI): Involves the bladder and urethra. Treated with oral antibiotics.
• Pyelonephritis (Upper UTI): Involves the kidneys; usually an ascending infection. Requires IV antibiotics and possible hospitalization to prevent sepsis and permanent renal scarring.
• Clinical Presentation by Age:
  • Neonates: Fever/hypothermia, poor feeding, lethargy, low urine output.
  • Infants: Fever, crying with urination, foul-smelling urine, abdominal distention.
  • Preschool/School-Age: Dysuria, abdominal pain, hematuria, new-onset enuresis.
  • Adolescents: Lower UTI (dysuria, urgency, frequency); Upper UTI (fever, chills, flank pain, CVA tenderness).
• Diagnosis:
  • Urinalysis (UA): Positive nitrites suggest UTI. Obtain via clean-catch for older children or catheterization for infants.
  • Urine Culture: The gold standard for diagnosis.
• Follow-Up: Renal ultrasound is done after the first febrile UTI in young children. A Voiding Cystourethrogram (VCUG) is performed if the ultrasound is abnormal or if UTIs are recurrent.

Vesicoureteral Reflux (VUR)

• Pathophysiology: Backward flow of urine from the bladder into the ureters and kidneys due to an incompetent ureterovesical valve.
• Diagnosis: Voiding Cystourethrogram (VCUG) using contrast dye.
• Grading: Graded I–V based on severity.
  • Grades I-II: Often resolve with growth; monitor and use prophylactic antibiotics.
  • Grades III-V: High risk of renal scarring; may require surgical ureteral reimplantation.

Nephrotic Syndrome

• Minimal Change Nephrotic Syndrome (MCNS): Accounts for $85\%$ of childhood cases. Most common between ages $2-7$. Often follows a viral illness.
• Pathophysiology: Increased glomerular permeability leading to massive proteinuria and hypoalbuminemia. This causes fluid to shift from the intravascular space to the interstitial space (edema).
• Manifestations: Weight gain, periorbital edema (worse in AM), ascites, scrotal/labial edema, skin pallor, and lethargy. Blood pressure is usually normal.
• Treatment: Corticosteroids are first-line. Immunosuppressants are used for relapses.
• Nursing Care: Monitor for infection (steroids cause immunosuppression). Avoid live vaccines during steroid therapy. Monitor daily weights and urine protein at home.

Acute Postinfectious Glomerulonephritis (APIGN)

• Cause: Usually follows a Group A Streptococcal infection (APSGN), occurring $10-21\,\text{days}$ after strep throat/skin infection.
• Pathophysiology: Immune complexes clog the glomeruli, causing inflammation and decreased GFR. Sodium and water are retained.
• Hallmark Findings: Tea-colored or smoky-brown urine (hematuria) and hypertension.
• Manifestations: Periorbital edema, oliguria, headache, and weight gain from fluid retention.
• Diagnostics: Positive ASO titer, elevated BUN/Creatinine, and RBC casts in urine.
• Treatment: Treat residual strep with Penicillin. Implement sodium and fluid restrictions. Administer diuretics and antihypertensives as needed.

Comparison: APIGN vs. Nephrotic Syndrome

• Primary Problem: APIGN is inflammation; Nephrotic is permeability.
• Cause: APIGN is post-strep immune reaction; Nephrotic is glomerular membrane damage.
• Urine: APIGN has hematuria (tea-colored); Nephrotic has massive proteinuria.
• Albumin: Mildly low in APIGN; severely low in Nephrotic.
• Edema: Mild/moderate in APIGN; severe/generalized in Nephrotic.
• Blood Pressure: Hypertension is common in APIGN; BP is usually normal in Nephrotic.
• Key Lab: Elevated ASO titer/low C3 in APIGN; Massive proteinuria/hypoalbuminemia in Nephrotic.